Systems and Methods for Alternative Routing of Voice Over IP Originated Emergency Calls

ABSTRACT

Systems and methods are described for routing Voice over Internet Protocol (VoIP) originated emergency calls. Where registered location information is not available, the present invention can attempt to identify an appropriate emergency call receiving office based on available information regarding the caller&#39;s physical location. Such information can include the IP address of the caller and, where the VoIP device is a dual mode device, the location of the last cellular base station accessed by the device. Where registered location information does exist, the present invention offers methods for ensuring that the registered location information is not obsolete and in need of updating and, in some cases, providing a manual override of call routing to the caller.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.11/676,037, filed Feb. 16, 2007, the entirety of which is hereinincorporated by reference.

TECHNICAL FIELD

This invention relates generally to the routing of emergency 911telephone calls. More specifically, the invention relates to the routingof Voice over Internet Protocol (VoIP) 911 calls to an appropriateemergency call center based on a measured or estimated location of thecaller.

BACKGROUND OF THE INVENTION

Since a national introduction in 1965, Americans have come toincreasingly depend on universal access to emergency services via thedigits 9-1-1. The digits 911 have become synonymous with emergencytelephone calls, and it has been estimated that 200 million 911 callsare made each year in the United States. Universal use of these threedigits for access to emergency services gives callers ready access tostate and local emergency responders regardless of the jurisdiction fromwhich the call is being made. The system has become an effective andreliable conduit for directing life saving efforts of first respondersto where they are needed.

911 service generally falls into one of two categories, basic 911 andenhanced 911 (E911). Basic 911 service forwards a 911 call from atelephone service provider's switch to a geographically appropriateemergency call center. The call is merely forwarded to this center andno further information about the call is provided to the call center.The caller's identity and location are disclosed to an answeringoperator through discussions with the caller.

E911 service instead routes 911 calls using a selective router. Theselective router can route a call based on the calling number. Theselective router can query a selective router database (SRDB) using thecalling number (referred to in 911 terminology as automatic numberinginformation or ANI) to determine the appropriate public serviceanswering point (PSAP) for handling the call. The call and the ANI arethen forwarded to the PSAP which, in turn, queries a location databaseusing the ANI. The location data (referred to as automatic locationinformation or ALI) associated with the ANI is then provided to thePSAP. The ALI returned is a physical address; the integrity of which hasbeen verified by comparison with a separate database known as a MasterStreet Address Guide (MSAG). E911 calls are routed over a dedicatednetwork which is interconnected with, but separate from, the publicswitched telephone network (PSTN). The selective router, trunk linesconnecting the selective router and the PSAP, the ALI database, theSRDB, trunk lines between the ALI database and the PSAP, and the MSAGtogether comprise the dedicated wireline E911 network.

While first introduced on the wireline networks of the day, access toemergency services via dialing 911 on modern mobile devices has posedchallenges to the operation of the 911 emergency services network.Wireline access is commonly provided by a local exchange carrier, whichprovides service to a fixed business or residential location. Atelephone number of an account can therefore be easily and reliablyassociated with a corresponding location address in system databases, sothat 911 calls received from the number can be routed to an emergencycall center best situated to deal with any emergency that exists at thataddress.

The location of mobile and nomadic devices, however, is not so reliablydetermined. These devices retain their telephone numbers as they aremoved from place to place. Obtaining the required location informationfor the routing of such calls requires a wholly different, or at leastmodified, solution. Due to the public's reliance on and expectation ofthe availability of emergency help via dialing 911 on a telephonydevice, the Federal Communications Commission (FCC) has taken steps toensure reliable 911 service continues to be available via these newertechnologies.

Mobile telephony devices such as handheld cellular telephonescommunicate through a network of geographically distributed basestations. At any given time, an active cellular telephone iscommunicating primarily through one base station. Knowledge of thelocation of the base station with which the handset is communicating canprovide a rough estimate of the location of the handset. The coveragearea of a base station, however, can span many square miles. Although ahandset communicates primarily with one base station, transmissions fromother nearby base stations can be detected by the handset. Transmissionsfrom the handset can be picked up at other base stations as well. Bymeasuring the difference between the times of arrival of handsettransmitted signals at several base stations (with known locations), theposition of the handset can be determined with far more precision. Inaddition, handsets which include global positioning sensors can providelocation information obtained using positioning satellites orbiting theearth.

The FCC has directed mobile communication providers to make suchmeasurements of device location and provide accurate device location tocall routing services for 911 calls. This helps to ensure that emergencycalls placed via these mobile terminals are routed to the appropriatecall center regardless of the location of the device. Receiving PSAPsare given ANI and ALI for these calls.

More recently, the emergence of Voice over Internet Protocol (VoIP)services has presented yet another challenge to the proper routing of911 calls. VoIP telephony services transmit and receive voice data inpackets having a format appropriate for transmission over the Internet.Instead of a traditional PSTN line, voice signals are sent over abroadband Internet connection and routed over the Internet. Throughinterconnections with the PSTN, VoIP calls can be sent to and receivedfrom the PSTN.

While a VoIP account generally has a static telephone number, the IPaddress of the broadband Internet connection over which the account isused can be dynamic. Furthermore, even if a static IP is utilized, thereis no database which reliably maps IP addresses to physical addresses(although as discussed below an estimate of the location of the physicallocation where the IP address is being used can be made). In addition,the VoIP equipment can be moved from one location to another so theequipment and the account can be used over more than just a singlebroadband Internet connection.

Upon first offering telephony services, VoIP providers did not havefacilities in place for providing location specific information to the911 emergency network. VoIP users expecting normal 911 access were, insome cases, routed to emergency call centers several hundreds of miles(or more) away from the caller's physical location. Incidents such asthese prompted the FCC to issue a number of requirements applicable tothe provision of VoIP services and the availability of reliable 911access via these services. These requirements can be found in “FirstReport and Order and Notice of Proposed Rule Making FCC 05-0116” theentirety of which is herein incorporated by reference.

The FCC order requires all interconnected VoIP providers (those whoconnect calls to the PSTN) to send 911 calls, a call back number (ANI),and a registered location for each call to the public service answeringpoint (PSAP), to a designated statewide default answering point, or toan appropriate local emergency authority that serves the caller'sregistered location. These calls are required to be routed using ANI andto be routed over the dedicated wireline E911 network.

According to the FCC order, to obtain the necessary information tofulfill the registered location requirement, VoIP providers must obtainservice location information from their customers, prior to theinstallation of service. If the service can be moved from one locationto another, the VoIP providers must offer a method for the customers toupdate the location information. At least one method of updating thisinformation must include the use of the customer premises equipment(CPE) of the VoIP installation. Providers cannot allow customers to optout of E911 service. The National Emergency Number Association (NENA)has published a proposed architecture for service providers to adopt forimplementing the FCC order. This document is entitled “Interim VoIPArchitecture for Enhanced 9-1-1 Services (i2)” and can be found athttp://www.nena.org/media/files/NENA_(—)08-001_V1_(—)12-06-05.pdf. Thisdocument is incorporated by reference herein in its entirety.

Delays in processing location information can occur after new VoIPinstallations. For example, where VoIP equipment is purchased at a pointof sale location, the purchaser (VoIP customer) can provide an addressfor the location where the VoIP will be used. The location can bevalidated at the point of sale to determine if it is an actual address.This validation, however, does not fully validate the address as MSAGcompliant such that it can be used in the E911 system. An MSAGvalidation can take up to 48 hours and can fail. In that case thelocation information supplied by the customer cannot be used by the E911system to enable the selective router to send the call to theappropriate PSAP. It is also possible that the address information couldbe corrupted (through a failed update for example) or obsolete due tothe VoIP equipment being moved to a location which differs from thelocation on record with the VoIP provider.

Systems and methods are therefore needed for providing a defaulttreatment in cases where location information supplied by the customeris unavailable or obsolete. Such systems and methods can route calls toemergency call centers which are capable of dispatching responders tothe source location of the call (as closely as that can be determinedfrom the available information) or to a center capable of quicklycommunicating with or capable of forwarding the call to the center.

SUMMARY OF THE INVENTION

The various embodiments of the present invention overcome theshortcomings of the prior art by providing, in one embodiment, a methodof routing a Voice over Internet Protocol (VoIP) originated 911 call byperforming an IP geolocation measurement based on an originating IPaddress of the 911 call and routing the 911 call to a call center basedon the results of the IP geolocation measurement. The call can be routedto a call center associated with city data if the measurement returnscity data. The call can be routed to a call center associated with statedata if the measurement returns state data. The call can also be routedto a call center associated with country data if the measurement returnscountry data. The 911 call can be routed to a default call center if theIP geolocation measurement fails or if the IP geolocation measurementdoes not return city data, state data, or country data.

Some embodiments, where the VoIP device is a dual mode device, canfurther include determining the location of the base station with whichthe dual mode device most recently communicated and comparing thelocation of the base station to the IP geolocation results to verify theresults of the IP geolocation measurement.

In some embodiments, the method can be initiated by a caller override of911 call routing which would otherwise be based on registered locationinformation associated with the VoIP account.

In another embodiment the invention provides a method of routing a VoIPoriginated 911 call from a dual mode device which includes determiningthe location of the base station with which the dual mode device mostrecently communicated and routing the 911 call to a call center based onthe location of the base station. This method can be initiated by acaller override of 911 call routing which would otherwise be based onregistered location information associated with the VoIP account.

The invention also provides a method of routing a VoIP 911 call bystoring a medium access control (MAC) address in a VoIP service providerserver; associating the stored MAC address as an authorized MAC addressfor the VoIP account; receiving a MAC address in a header of an IPpacket associated with the 911 call; comparing the received MAC addressto the authorized MAC address; checking the VoIP account records todetermine if the account has a registered location; and routing the 911call as an E911 call using the registered location information if theaccount has a registered location and the received MAC address matchesthe authorized MAC address. if the received MAC address does not matchthe authorized MAC address, the method can include the steps ofperforming an IP geolocation measurement based on an originating IPaddress of the 911 call, and routing the 911 call to a call center basedon the results of the IP geolocation measurement. In some embodimentswhere the VoIP device is a dual mode device and the received MAC addressdoes not match the authorized MAC address, the method can include thesteps of determining the location of the base station with which thedual mode device most recently communicated, and routing the 911 call toa call center based on the location of the base station.

In addition, the invention provides a method of routing a VoIPoriginated 911 call by providing a location indication on a display ofthe VoIP device used to place the 911 call, the location indicationbeing associated with the VoIP account used to place the 911 call,providing a notification on the display that the 911 call will be routedbased on the location indicated, and providing a selectable calleroverride option for overriding the routing of the 911 call based on thelocation indicated. The method can also include the steps of receiving acaller override signal and, in response to the caller override signal,performing an IP geolocation measurement based on an originating IPaddress of the 911 call, and routing the 911 call to a call center basedon the results of the IP geolocation measurement. Where the VoIP deviceis a dual mode device, the method can also include receiving a calleroverride signal and, in response to the caller override signal,determining the location of the base station with which the dual modedevice most recently communicated, and routing the 911 call to a callcenter based on the location of the base station.

In addition, a selectable list of routing options can be provided on thedisplay. A routing selection can be received and the 911 call can berouted based on the selection. The selectable list can include a list ofaddresses previously associated with the VoIP account, an option forrouting based on an IP geolocation measurement, and/or an option forrouting based on the location of a base station most recently accessedby the VoIP device.

The foregoing has broadly outlined some of the aspects and features ofthe present invention, which should be construed to be merelyillustrative of various potential applications of the invention. Otherbeneficial results can be obtained by applying the disclosed informationin a different manner or by combining various aspects of the disclosedembodiments. Accordingly, other aspects and a more comprehensiveunderstanding of the invention may be obtained by referring to thedetailed description of the exemplary embodiments taken in conjunctionwith the accompanying drawings, in addition to the scope of theinvention defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an exemplary Voice over InternetProtocol (VoIP) environment in which the present invention can beemployed.

FIG. 2 illustrates a flow diagram of a method for routing a VoIP 911call based on IP geolocation where there is no registered locationinformation associated with the VoIP account placing the emergency call,according to the present invention.

FIG. 3 illustrates a flow diagram of a method for alternate routing of adual-mode device originated 911 call using the location of the basestation with which the device most recently communicated, according tothe present invention.

FIG. 4 illustrates a flow diagram of a method for routing a VoIP 911call in accordance with aspects of the routing methods presented in FIG.2 and FIG. 3 and performing a crosschecking function, according to thepresent invention.

FIGS. 5A and 5B illustrate methods for alternative routing of anemergency call based on the media access control (MAC) address of thewireless access point being utilized, according to the presentinvention.

FIGS. 6A and 6B illustrate methods for including user interaction in theemergency call routing process, according to the present invention.

FIG. 7 illustrates a method for routing a VoIP 911 call with multiplevalidated addresses, according to the present invention.

FIG. 8 illustrates another method for routing a VoIP 911 call withmultiple validated addresses, according to the present invention.

FIG. 9 illustrates yet another method for routing a VoIP 911 call withmultiple validated addresses, according to the present invention.

FIG. 10 illustrates a dual-mode device with location overridecapabilities, according to the present invention.

FIG. 11 illustrates a dual-mode device with a location selection screen,according to the present invention.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosedherein. It must be understood that the disclosed embodiments are merelyexemplary of the invention that may be embodied in various andalternative forms, and combinations thereof. As used herein, the word“exemplary” is used expansively to refer to embodiments that serve as anillustration, specimen, model or pattern. The figures are notnecessarily to scale and some features may be exaggerated or minimizedto show details of particular components. In other instances, well-knowncomponents, systems, materials or methods have not been described indetail in order to avoid obscuring the present invention. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a basis for the claims and asa representative basis for teaching one skilled in the art to variouslyemploy the present invention.

In one embodiment, the present invention finds application using adual-mode wireless equipment. As used herein, the term dual-modewireless equipment (or device, handset, etc.) is a communication devicewhich can communicate wirelessly via a cellular network, and can alsocommunicate using VoIP. Any wireless standard can be employed for thecellular communication mode including, but not limited to, GSM,IS-95/CDMA, W-CDMA, UMTS, etc. Communications made in the VoIP mode canbe conducted over a comparatively short range radio link (e.g.,WiFi/IEEE 802.11x or BLUETOOTH®) with a wireless access point whichprovides access to a broadband Internet connection.

Dual-mode wireless equipment can provide a wireless (cellular) customerwith, for example, the convenience of communicating using their wirelesshandset via VoIP while at home so wireless plan air time is not spent onsuch calls. With such a system in place, many customers may elect todiscontinue traditional PSTN wireless service at their home. A dual-modesystem can also make a separate VoIP service redundant and unneeded.While the invention is described with reference to a dual mode wirelessequipment embodiment, the invention should not be considered to belimited to dual mode cellular/VoIP installations. It will be apparent toone of skill in the art that many aspects of the present invention areapplicable not only dual mode embodiments, but also to standalone VoIPinstallations which do not incorporate dual mode functionality.

Referring now to the drawings in which like numerals indicate likeelements throughout the several views, the drawings illustrate certainof the various aspects of exemplary embodiments of the invention.

FIG. 1 shows an exemplary environment 100 in which the methods of thepresent invention can be employed. The figure is marked as prior art dueto the existence of such systems in the art. Components of this systemcan be modified, however, to incorporate the present invention. Whensuch modifications are made, the modified system should not beconsidered as prior art.

A telephone 102 is connected to a Voice over Internet Protocol (VoIP)gateway 104. The VoIP gateway 104 is in turn connected to a router 106.A dual-mode handset 108 can communicate with a wireless access point 110and also with a base station 112. Communication with the wireless accesspoint 110 can occur via WiFi (according to the IEEE 802.11x standard) orvia some other wireless protocol. Communication with the base station112 can occur via any of the known cellular communication protocols. Thewireless Access Point 110 is connected to the router 106. Alternatively,the router 106 can include an integrated wireless access point 110. Therouter 106 connects to a cable/DSL modem 114. The cable/DSL modem 114connects to an Internet service provider 116 to access the Internet 118.It should be understood that the router 106 can instead connect to theInternet via a T1 line, a T3 line or the like. A VoIP service provider120 is connected to the Internet 118 and to the Public SwitchboardTelephone Network (PSTN) 122. Packetized voice information can bereceived by the VoIP service provider 120 from the dual-mode handset 108and/or the telephone 102. This voice information can be converted into aformat suitable for transmission over the PSTN 122 as is known in theart. The VoIP service provider 120 can receive voice calls intended forthe dual-mode handset 108 and the telephone 102 from the PSTN 122, andconvert the voice information therein into IP packets for delivery tothe telephone 102 and/or the dual-mode handset 108.

The base station 112 is connected to a base station controller 124,which in turn connects to a mobile switching center 126. The mobileswitching center 126 can access customer records stored in a homelocation register 128. The mobile switching center 126 also connects tothe PSTN 122 so that wireless originated calls can be terminated at thePSTN 122 and PSTN 122 originated calls can be terminated at the wireless(cellular) network. Although the elements shown are typical elements ofa GSM wireless network, these elements are shown for purposes ofexample. The methods of the current invention are equally applicable toany cellular wireless technology.

The present invention provides systems and methods for routing VoIPoriginated 911 calls. While the FCC order requires that a VoIPinstallation have a registered location for the purposes of routing 911calls, in some instances, as mentioned above, registered location datamay not be available or may indicate an incorrect or obsolete location.In the case of an emergency call where no registered location data isavailable, it can still be advisable to attempt to connect the 911 callto an appropriate receiving facility. In such cases alternate sources ofdata can be employed to attempt to connect the caller to the mostappropriate emergency call center that can be identified. Although thecall might not be routed to the Public Service Answering Point (PSAP)designated for the caller's actual physical location, the call can berouted to an emergency call center which can dispatch first respondersto the location or can transfer the call to a center with that ability.

FIG. 2 shows a method 200 for routing a VoIP 911 call based on IPgeolocation where there is no registered location information associatedwith the VoIP account placing the emergency call. The method 200 startsat block 201. At block 202, a VoIP originated call is received. Thiscall can be received at the VoIP service provider 120. The VoIP serviceprovider 120 can query its account databases to determine if the accountis associated with a registered location. At block 204, it is determinedif the account is associated with a registered location. If the accountis associated with a registered location, processing continues to block206 where the 911 call is processed as an E911 call in compliance withthe FCC order using the registered location information. The method 200then ends at block 208. From block 204, if the account is not associatedwith a registered location, processing continues to block 210. At block210 an IP geolocation measurement based on the originating IP address isperformed.

As used herein, the term IP geolocation refers to the location of an IPaddress which can be estimated or measured based on known locations ofInternet routers in the routing path of the IP address.

At block 212, if IP geolocation results are not available (e.g., themeasurement failed), processing continues to block 214 where the call isrouted to a default emergency call center. From block to 212, ifgeolocation results are available, processing continues to block 216. Atblock 216, if city data is available from the geolocation results,processing continues to block 218 where the call is routed to theauthorized call center corresponding to the city indicated. If no citygeolocation data is available, processing continues to block 220 where acheck is performed to determine if state geolocation data is available.If state data geolocation data is available, at block 222, the call isrouted to the authorized call center corresponding to the stateindicated. If no state geolocation data is available, processingcontinues to block 224 where a check is performed to determine if nationgeolocation data is available. If nation data is available, at block 226the call is routed to the authorized call center corresponding to thecountry indicated. If no nation IP geolocation data is available,processing continues to block 214 where the call is routed to a defaultemergency call center. While the method 200 shown in FIG. 2 might notresult in the 911 call being delivered to the E911 PSAP corresponding tothe location of the caller, the method 200 attempts to deliver the callto the nearest emergency call center that the resolution of the IPgeolocation results can provide.

FIG. 3 shows a method 300 for alternate routing of a dual-mode device108 originated 911 call using the location of the base station 112 withwhich the device 108 most recently communicated. The dual-mode device108 can store an identifier in memory which uniquely identifies the basestation 112 with which it most recently communicated. This identifiercan be transmitted to the VoIP service provider 120 via the wirelesslink to the access point 110 and across the Internet 118. For thisdual-mode example, the VoIP service is provided by the cellular serviceprovider or by an affiliated VoIP partner. In either case, the VoIPservice provider 120 has access to the cellular service provider'sdatabase linking base stations 112 with their unique identifiers andtheir locations. Alternatively, or in addition, the VoIP serviceprovider 120 can receive a unique identifier for the device 108 and/orcellular account and retrieve the location of the base station 112 withwhich the device 108 last communicated based on this information. Forexample, the device 108 can transmit its International Mobile SubscriberIdentity (IMSI) to the VoIP service provider 120, which can query thecellular provider's HLR 128 to determine the last base station 112 withwhich the device 108 communicated.

The method 300 starts at block 302 and proceeds to block 304 where aVoIP originated 911 call is received from a dual-mode device 108. Atblock 306, if the originating VoIP account is associated with aregistered location, processing continues to block 308. At block 308, acall is routed as an E911 call using the registered location accordingto the FCC order. The method 300 ends at block 310. At block 306, if theaccount is not associated with a registered location, processingcontinues to block 312. At block 312, identifying information regardingthe most recently accessed base station 112 is retrieved. As mentionedabove this can comprise receiving a unique identifier for the basestation 112 from the dual-mode 108 device or receiving an identifier forthe device 108 or cellular account and retrieving the base station 112information from the cellular network. At block 314, if no base station112 information is available, processing continues to block 316 wherethe call is routed to a default emergency call center. The method endsat block 310. From block 314, if base station 112 information isavailable, processing continues to block 318. At block 318, the locationof the base station 112 corresponding to the identifying information isdetermined. This determination can be made by querying the appropriatecellular network databases which include associations between basestation 112 identifiers and the physical locations of those basestations 112. Processing then continues to block 320 where the emergencycall is routed to the authorized call center serving the areacorresponding to the base station's 112 determined location. Again,while the method 300 might not result in the 911 call being delivered tothe E911 PSAP corresponding to the location of the caller, the method300 attempts to deliver the call to the nearest emergency call centerthat can be determined based on the last base station 112 contact of thedevice 108.

FIG. 4 shows a method 400 which combines elements of the IP geolocationmethod 200 of FIG. 2 with the base station 112 location method 300 ofFIG. 3, crosschecking the results of one method using another. Themethod 400 starts at block 402. At block 404, a VoIP originated 911 callfrom a dual-mode device 108 is received. Processing continues to block406 where the account is checked to determine if the account isassociated with a registered location. If so, processing continues toblock 408 when the call is processed as an E911 call in accordance withthe FCC requirements using the registered location information. Themethod ends at 410. From block 406, if there is no registered locationinformation associated with the account, processing continues to block412 where an IP geolocation measurement is performed based on theoriginating IP address for the call. Processing continues to block 414where identifying information regarding the most recently accessed basestation 112 is retrieved. As mentioned above, this information can beused to determine the location of the most recently accessed basestation 112. Processing continues to block 416. If IP geolocationresults are not available at block 416 processing continues to block418. At block 418, if base station 112 information is available,processing continues to block 320 of FIG. 3. If no base station 112information is available at block 418, processing continues to block420, where the call is routed to a default emergency call center. Fromblock 416, if IP geolocation results are available processing continuesto block 422. If base station 112 information is not available at block422, processing continues to block 216 of FIG. 2. If base station 112information is available at block 422, processing continues to block424. At block 424, city information from the IP geolocation measurementis checked against the base station 112 location information. If theinformation from these two sources is consistent, processing continuesto block 426 where the call is routed to the authorized call centercorresponding to the city indicated.

If the city information is not consistent between the two sources atblock 424, processing continues to block 428. At block 428, stateinformation from the two sources (the IP geolocation measurement and thebase station 112 location information) is compared to see if it isconsistent. If so, processing continues to block 430 where the call isrouted to the authorized call center corresponding to the stateindicated. If the state information from the two sources is notconsistent, processing continues to block 432 where the countryinformation from the two sources is compared. If the country informationfrom the two sources is consistent processing continues to block 434where the call is routed to the authorized call center corresponding tothe country indicated. If the country information from the two sourcesis inconsistent, processing continues to block 420 where the call isrouted to the default emergency call center, and the method 400 ends atblock 410.

FIGS. 5A and 5B show methods 500 and 518, respectively, for alternativerouting of an emergency call based on the media access control (MAC)address of the wireless access point 110 being utilized. As is known inthe art, a MAC address is a unique (or quasi-unique) identifier forEthernet (IEEE 802.3) networking devices. At the point-of-sale of thedual-mode device 108 or prior to the enablement of the VoIP mode of thedual mode phone, the purchaser can be asked to provide the MAC addressof the wireless access point 110 located at the purchaser's home whichwill be used with the dual-mode device 108. This information can berequested at the same time the purchaser is asked for the registeredlocation information. This MAC address can be associated with the VoIPaccount by the VoIP service provider 120. This information canthereafter be used to ensure that VoIP calls originated from thedual-mode device 108 are being made at the caller's home location. Usingthis information in this way does have potential flaws.

For example, the user can move the wireless access point 110 to anotherlocation, in which case the MAC address will match the addressassociated with the account even though the physical location of thecaller has changed. In addition, the user could also purchase a newwireless access point 110 for use at home. In this case the physicallocation of the caller has not changed by the new wireless access pointhas a different MAC address. Regardless, the use of an MAC address inthis manner can provide potential benefits. For example, a detectedchange in MAC address can be used to flag an account or a call assuspect with regard to its registered location information. A change inMAC address can also be used to prevent a caller from placing a VoIPcall until the MAC address associated with the account has been updated.At that time the user can be prompted to update their registeredlocation information. As mentioned above, however, in the case of anemergency call it might be considered prudent to process the callregardless of an inconsistency with an associated MAC address.

FIGS. 5A and 5B show methods 500 and 518, respectively, forincorporating a check as to whether the MAC address of a wireless accesspoint being used to place a VoIP call matches the MAC address associatedwith the VoIP account in a 911 call routing process.

FIG. 5A shows method 500 which starts at block 502. At block 504, a VoIPoriginated 911 call is received from a dual-mode device 108. Processingcontinues to block 506 where a MAC address of the wireless access point110 being used by the dual-mode device 108 is retrieved. Thisinformation can be retrieved from the IP packets sent from a wirelessaccess point 110 to VoIP provider 120 as is known in the art. Processingcontinues to block 508 where a check is performed to determine if theaccount is associated with a registered location. If no registeredlocation is associated with the account, processing continues to block210 of FIG. 2. From block 508, if the account is associated with aregistered location, processing continues to block 512. At block 512,the MAC address retrieved from the access point 110 is compared to theMAC address associated with the account. If the MAC addresses match,processing continues to block 514 where the call is processed accordingto the FCC order based on the registered location information. If theMAC addresses do not match, indicating that there is a strongpossibility that the measured location information is obsolete,processing continues to block 210 of FIG. 2. The method ends at block516.

FIG. 5B shows a method 518 which is similar to the method 500 of FIG. 5Aexcept that at block 528 the process continues to block 312 of FIG. 3instead of block 210 of FIG. 2 (a last base station 112 accessed methodis performed instead of the IP geolocation method.) It should also beunderstood that a similar method can be used along with the combined IPgeolocation and last base station 112 accessed method.

FIGS. 6A and 6B show methods 600 and 618, respectively, for includinguser interaction in the emergency call routing process. FIG. 6A showsmethod 600 which starts at 602. At block 604, a 911 call is detectedbeing made from a VoIP device 108. This method can be implemented, forexample, by a processor included in a VoIP device 108 or by acombination of VoIP service provider 120 systems and the processor.Processing continues to block 606 where the address being used to routethe 911 call is shown on a display of the device 108. Processingcontinues to block 608 where the caller is presented with an opportunityto override 911 call routing according to the displayed address. Acaller override can be useful where the caller's current location isdifferent from the address shown on the display. Such a situation canoccur, for example, where registered location information has becomeinaccurate due to a move by the user and a subsequent failure to updatethe information. At block 610, if the caller overrides the routingprocess then at block 612 processing continues to block 210 of FIG. 2.If the caller does not override the routing process, processingcontinues to block 614 where the call is processed as an E911 call. Themethod 600 then proceeds to block 616 and the method 600 ends.

FIG. 6B shows a method 618 which is similar to the method 600 of FIG. 6Aexcept that at block 630 processing continues to block 312 of FIG. 3.That is, the caller override initiates a routing method based on thebase station 112 last accessed by a dual mode device 108. It should beunderstood that the caller override could also lead to the use of thecombined IP geolocation and last base station 112 accessed routingmethod.

FIG. 7 shows a method 700 which starts at block 702. At block 704, a 911call is detected as being made from a VoIP device 108. Processingcontinues to block 706 where the address being used to route the 911call is shown on the device 108 display. At block 708, the caller ispresented with the opportunity to override routing of the 911 call basedon the displayed address. At block 710, if the caller does not overridethe routing, processing continues to block 712 where the call is routedusing the address displayed and the method ends at block 714. If thecaller overrides the routing at block 710, processing continues to block716 where the memory of the device 108 and/or VoIP service provider 120account information is checked to determine if there are additional MSAGvalidated addresses associated with the VoIP call/account. If there areno such addresses, processing continues to block 210 of FIG. 2. Itshould be understood that block 718 could also lead to block 312 of FIG.3 or a combined IP geolocation and last base station 112 accessedrouting method as described above. If additional validated addresses arefound at block 716, processing continues to block 720 where theseaddresses are presented to the caller on the device 108 display in aselectable format. Processing continues to block 722 where, if thecaller does not select an address, a timeout can occur and processingcan continue to block 210 of FIG. 2. If the caller does select anaddress, processing can continue to block 712 where the call isprocessed as an E911 call based on the address selected by the caller.

FIG. 8 shows a method 800 also involving the use of additional validatedaddresses. The method starts at block 802 and continues to block 804where a 911 call is detected as being made from a VoIP device 108.Processing continues to block 806 where the memory of the device 108and/or VoIP service provider 120 account information is checked todetermine if there are additional MSAG validated addresses associatedwith the VoIP call/account. If there are no such addresses, processingcontinues to block 808 where the call is processed using the registeredlocation associated with the account (the existence of which is presumedfor the purposes of this example) and the method ends at block 810. Ifmore than one MSAG validated address is found for the call/account,processing continues to 812 where an IP geolocation measurement isperformed on the originating IP address. Processing continues to block814 where a check is performed to determine if any of the addressesassociated with the account are within some maximum radius of theresults of the IP geolocation measurement. The maximum radius can be amaximum distance that is considered to be an acceptable distance betweenthe geolocation measurement results and one of the associated addressesfor that address to be used as the registered location for the emergencycall. If there is an associated address that is with a maximum radius ofthe geolocation measurement, that address is used as the registeredlocation and processing continues to block 808. If no address is foundwithin the maximum radius, processing continues to block 212 of Figure 2where the call is routed based on the results of the IP geolocationmeasurement.

FIG. 9 shows a method 900. The method starts at block 902 and continuesto block 904 where a 911 call is detected as being made from a VoIPdevice 108. Processing continues to block 906 where the memory of thedevice 108 and/or VoIP service provider 120 account information ischecked to determine if there are additional MSAG validated addressesassociated with the VoIP call/account. If there are no such addresses,processing continues to block 908 where the call is processed using theregistered location associated with the account (again, the existence ofwhich is presumed for the purposes of this example) and the method endsat block 910. If more than one MSAG validated address is found for thecall/account, processing continues to block 912 where the location ofthe last base station 112 accessed by the dual-mode device 108 isdetermined. Processing continues to block 914 where a check is performedto determine if any of the addresses associated with the account arewithin some maximum radius of the base station 112 location. If there isan associated address that is within a maximum radius of the basestation 112 location, that address is used as the registered locationand processing continues to block 908. If no address is found within themaximum radius, processing continues to block 318 of FIG. 3 where thecall is routed based on the location of the base station 112.

FIG. 10 shows a dual-mode device 1000. The device 1000 has a display1002, a keypad 1004, softkeys 1006, 1008, a directional controller 1010,a select button 1012, a send key 1014, and an end key 1016. The display1002 illustrates an indication 1018, which shows that a current 911 callis being routed consistent with the address shown. A softkey indicator1020 is shown above the softkey 1006. Pressing and holding the softkey1006 will override the routing of the 911 call based on the addressshown.

FIG. 11 shows the dual-mode device 1000 having a display indication 1100which offers choices 1102 of current locations to the user. Choices 1through 3 can be validated MSAG addresses associated with the accountand/or stored in a device memory. Choice 4 shows the location of thecaller as determined by IP geolocation. Choice 5 shows the location ofthe caller is determined based on the last base station 112 accessed bythe device 108. Choice 6 is to route the call to a national emergencycall center. Selection box 1104 can be moved from one choice to anotherusing the directional controller 1010 and a choice can be selected bypressing the select key 1012. Alternatively, or in addition, the keypadnumber corresponding to the choice can be pressed and held. Upon thecaller making a selection, the call is routed consistent with thecaller's selection.

It should be understood that the sequences of method steps describedherein are provided for purposes of example and are not the onlysequences in which the present invention can be embodied. Manyalternative sequences using combinations of the various methodsdisclosed will be apparent to one of skill in the art upon study of thisdisclosure. Such alternative sequences are within the scope of thepresent invention.

The law does not require and it is economically prohibitive toillustrate and teach every possible embodiment of the present claims.Hence, the above-described embodiments are merely exemplaryillustrations of implementations set forth for a clear understanding ofthe principles of the invention. Variations, modifications, andcombinations may be made to the above-described embodiments withoutdeparting from the scope of the claims. All such variations,modifications, and combinations are included herein by the scope of thisdisclosure and the following claims.

What is claimed is:
 1. A device for routing a 911 call from a callerdevice, comprising: a processor; and a memory having stored thereoninstructions which, when executed by the processor, cause the processorto perform operations comprising: receiving a caller override signalfrom the caller device for overriding registered location informationassociated with an account of the caller, wherein the caller overridesignal is initiated by the caller device responsive to the callerdevice: displaying a geographical address on a display of the callerdevice, wherein the geographical address indicates the registeredlocation information, providing a notification on the display that the911 call from the caller device will be routed based on the geographicaladdress, providing a selectable caller override option for overridingthe routing of the 911 call based on the geographical address, andreceiving a selection of the caller override option; and in response tothe caller override signal: performing an Internet Protocol (IP)geolocation measurement based on an originating IP address of the 911call; and routing the 911 call to a call center based on the results ofthe IP geolocation measurement, wherein if the IP geolocationmeasurement returns partial geolocation data, the 911 call is routed tothe call center associated with a highest resolution part of thegeolocation data.
 2. The device of claim 1, wherein the partialgeolocation data from the IP geolocation measurement includes statedata, and the instructions, when executed by the processor, furthercause the processor to perform routing the 911 call to a call centerassociated with the state data if the measurement returns the state databut does not return city data.
 3. The device of claim 1, wherein thepartial location data from the IP geolocation measurement includescountry data, and the instructions, when executed by the processor,further cause the processor to perform routing the 911 call to a callcenter associated with the country data if the measurement returns thecountry data but does not return at least one of city data or statedata.
 4. The device of claim 1, wherein the instructions, when executedby the processor, further cause the processor to perform routing the 911call to a default call center if the IP geolocation measurement fails.5. The device of claim 1, wherein the instructions, when executed by theprocessor, further cause the processor to perform routing the 911 callto a default call center if the IP geolocation measurement does notreturn any of city data, state data, or country data.
 6. The device ofclaim 1, wherein the caller device is a dual mode cellular and Voiceover Internet Protocol (VoIP) device.
 7. The device of claim 6, whereinthe instructions, when executed by the processor, further cause theprocessor to perform: determining the location of a base station withwhich the dual mode device most recently communicated; and comparing thelocation of the base station to the IP geolocation results to verify theresults of the IP geolocation measurement.
 8. A caller device,comprising: a display configured to display a geographical address ofthe caller device, wherein the geographical address indicates registeredlocation information associated with an account of the caller, and toprovide a notification that a 911 call from the caller device will berouted based on the geographical address; and a softkey configured toprovide a selectable caller override option for overriding the routingof the 911 call based on the geographical address, wherein upon receiptof selection of the caller override option, the caller device sends acaller override signal to a service provider for overriding theregistered location, and in response to the caller override signal, theservice provider performs an Internet Protocol (IP) geolocationmeasurement based on an originating IP address of the 911 call from thecaller device and routes the 911 call to a call center, based on theresults of the IP geolocation measurement, wherein if the IP geolocationmeasurement returns partial geolocation data, routing includes routingthe 911 call to the call center associated with a highest resolutionpart of the geolocation data.
 9. The caller device of claim 8, whereinthe partial location data includes state data, and the service providerroutes the 911 call to a call center associated with the state data ifthe IP geolocation measurement returns the state data but does notreturn city data.
 10. The caller device of claim 8, wherein the partiallocation data includes country data, and the service provider routes the911 call to a call center associated with the country data if the IPgeolocation measurement returns the country data but does not return atleast one of city data and state data
 11. The caller device of claim 8,wherein the service provider routes the 911 call to a default callcenter if the IP geolocation measurement fails.
 12. The caller device ofclaim 8, wherein the service provider routes the 911 call to a defaultcall center if the IP geolocation measurement does not return any ofcity data, state data, or country data.
 13. The caller device of claim7, wherein the caller device is a dual mode cellular and Voice overInternet Protocol (VoIP) device.
 14. The caller device of claim 13,wherein the service provider determines the location of the base stationwith which the dual mode device most recently communicated and comparesthe location of a base station to the IP geolocation results to verifythe results of the IP geolocation measurement.